ARM: imx6q-sabrelite: Setup CLKO IOMUX

In order to have audio functional on mx6qsabrelite, it is necessary
to setup the IOMUX for MX6Q_PAD_GPIO_0__CCM_CLKO pins as it provides
the audio clock.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>